Experimental study of heat transfer and pressure drop characteristics for flow of water inside circular smooth and micro-fin tubes

평활관 및 미세휜관 내에서의 물을 이용한 열전달 및 압력강하 특성에 관한 실험

Heat transfer and pressure drop for single phase flow of water in circular smooth and micro-fin tubes are measured. Copper tubes of 9.52 and 7mm outer diameter were used. The internal roughness in micro-fin tubes was formed by spiral grooves having $25^{\circ}$ helx angle, 0. 12mm fin height and 0.454mm pitch in 9.52mm tubes; $18^{\circ}$ helix angle, 0.15mm fin height and 0.322mm pitch in 7mm tubes. The measured friction factor and heat transfer coefficient are compared with relevant previous works, and the correlations for micro-fin tube are developed.